A transparent adhesive sheet is widely used as, for example, a transparent adhesive tape. The transparent adhesive sheet is not only excellent in appearance, but also does not hide an adherend even after attached to the adherend. Therefore, its application is extraordinarily wide.
The transparent adhesive sheet often includes an adhesive layer formed with an adhesive agent on the back surface side. Such a transparent adhesive sheet also includes, on the front surface side, a release layer containing a release agent having release properties to the adhesive agent. The long transparent adhesive sheet configured as described above, which is wound around a core material, is commercially available. In such a wound state, the adhesive agent is in contact with the release layer of its immediately inner layer. This prevents the transparent adhesive sheet from being bonded to the transparent adhesive sheet itself. Therefore, a user can release the adhesive layer which has been temporarily bonded to the release layer, thereby using the transparent adhesive sheet sequentially from the outer circumferential side.
Incidentally, as a release agent to be used in the release layer, a water-repellent or oil-repellent component such as silicone resins and silicone oils is added. These release agents are likely to repel printed ink in general. Therefore, it is difficult to perform printing on the release layer. In order to prevent printing from being performed on the release layer, for example, it is also conceivable to previously perform printing on a layer to become a base material or the like and then forming the release layer or the adhesive layer. However, in this method, a request to perform printing when bonding the transparent adhesive sheet cannot be met.
To address this concern, there is proposed a technology of printing on an adhesive tape by irradiation with laser beams (Patent Literature 1). This literature describes that according to this method, “high-mix small-lot individual printing can be simply manufactured” by irradiation with laser beams (Patent Literature 1, paragraph [0001]). It is noted that as described herein, printing which has been already performed when a transparent adhesive sheet is supplied to a user is referred to as simply “preprinting”, and, for example, printing which is performed during in use is referred to as “printing” hereinafter. It is noted that what is printed is not particularly limited. What is printed includes not only letters but also designs, color patterns, pictures, photographs, and the like.
There is also proposed a technology of forming a release layer as a top layer on the front surface side of a thermal color developing paper sheet and forming an adhesive layer as a bottom layer on the back surface side, and thereafter thermally printing on the thermal color developing paper sheet (Patent Literature 2).